Regulating device for telephone relays and transmitters.



N0. 836,611. PATENTED NOV. 20, 1906.

H. E. SHREEVE. I

REGULATING DEVICE FOR TELEPHONE RELAYS AND TRANSMITTERS.

APPLICATION FILED OUT. 26. 1905.

2 SHEETS-SHEET 1.

d d I T W L IIIIWIIIIIIIII lllllllllllllll w N INVENTOR.

W5. WM

1 ATTORNEY.

PATENTED NOV. 20, 1906.

H. E. SHREEVE.

REGULATING DEVICE FOR TELEPHONE RELAYS AND TRANSMITTBRS.

APPLIQATIOR' FILED OCT. 26. 1905.

2 SHEETSSHEET 2 T HV'VENTOR.

W6. JM;

ATTORNEY.

WITNESSES:

HERBERT 11 SHREEVEyOF NEWTON, MASSACHUSETTS, ASSIGNOR TO AMERICAN TELEPHONE AND TELEGRAPH COMPANY, A CORPORA- TION OF nnwronx.

REG ULATING DEVICE FOR TELEPHONE RELAYS AND TRANSMITTERS.

TOM;- who'm it may concern.- I .'Be it known that I, HERBERT E. SHREEVE, residin at Newton, in ,the county of'Middlesex an State of Massachusetts, haveinvented certain Im rovements in Regulating Devices for Tele one Relays and Transmitters,

" of which'the ollowing is a specification.

This invention relates to improvements in telephonic instruments or apparatus (such as current reinforcers, relays, and transmitters) which embody as an element thereof a granular carbon button or micro hone; but the invention is especially inten ed as an im rovement upon the telephone current reinorcers or relays of my Patents No. 791,655 and No. 791,656, dated June 6, 1905.

This invention is designed as' a remedy against the packing of the'carbon granules in packing im.

sistanceand efiiciency should'it become abnormally compacted.

In relays such as described in my patents above enumerated and to a lesser extent in the 'anular carbon-transmitter used indepen ently of relays there is a tendency of the granules in the carbon-chamber to pack, such airing the resistance -varying properties 0 the mass in re ponding to'relative vibrations of theelect odes, and consequently diminishing the transmitting efliciency of the ap aratus. Such packlngof the carbon ranu es, a defect inherent in instruments '0 this type is, it is believed, due in part to the natural tendency of the carbon granules to settle toward the bottom of the chamber, particularly under the influence of the slight relative vibrations of the electrodes in the normal operation of'the instrument, in

part to theconstant and slight vibrations going on everywhere, and particularly in bui ings where such a paratus is likely to be located, in part to t e expansion effects of heat Specification of Letters Patent.

Application filed October 26,19 05. Serial No. 284,449.

'therethrough in the norm Patented Nov. 20, 1906.

generated in the button; including the granular carbon thereof, by the assage of currentv til operation of the paratus, and, possibly, to other causes 'ch need not be mentioned. In'the preferred embodiment of this invention the thermostatic device is so mechanically connected to a movable wall of the carbon-chamber or button that when heated to abnormal temperature it will draw out the movable wall to increase the interior dimensions of the chamber, and hence lessen the pressure upon the granules. The thermostatic device is so constructed that with the carbon granules in their normal condition of looseness and resistance the current which said carbon permits to pass to the thermostatic device will not roduce in the latter suflicient heat to cause it to move the wall of the chamber, the heat thus produced being balanced by dissipation thereof away from the thermostat, due to conduction and radiation; but this equilibrium is disturbed when any change takes place in the local circuit. Hence when the carbon granules become acked arid the resistance to the current pass-- in therethrough from one terminal to the ot er thus reduced the considerably-increased current thus permitted to circulate generates abnormal heat in the thermostatic evice,'which thereupon draws. out the movable wall, loosening the mass of carbon particles and the contact thereof with the elec-. trodes. This results in a sudden material increase of the resistance of the button and like diminution in the current flowing throug the thermostatic device and the heat generated in the latter. The'temperature drops and the thermostatic device contracts, forcing the movable wall inward, and thereby decreasing the capacity of the chamber, (for the instant to probably less than its normal size,) the veloclty of motion in this direction being accentuated by the resiliency of the support of the wall. The more or less abrupt contact of the inwardly-moving Wall with the carbon .mass, previously permitted to relax by the outward movement, completes-the rearrangement of the microphonic particles, which accordingly are again loosened within the chamber. This is believed to be the correct explanation of the manner the acking.

Tii

sup orted by disk'8.

in which the ex ansion and contraction of the chamber e eats the loosenin of the acked carbon mass, although it as .been

ound impossible to actually observe the changes which take lace therein in operation owing to the inc osing of said mass, the almost imperce tible movements which effect the changes an the swiftly successive and recurrent character of the changes. It is of great importance, however, that the apparatus has in e present invention, embracing further certain details of construction, Will be more fully understood by reference to the accompanying drawings, wherein,

Figure 1 is a central elevation, partly in section, of an instrument embodying the principal features of my invention. Fig. 2 is a dlagram illustrating the connections of said instrument with a local battery, an induction-coil, and the main line, by which the current may be relayed in either direction. Figs. 3 and 3 are details of the instrument shown at Fig. 1. Figs. 4 and 4 are a modification of the thermostat. Fig. 5 is a telephone-transmitter embodying the main invention.

A is a metallic base-plate upon which isv mounted and held in position by screws (not shown) a centrally bored metal standard B, within which closely fits, as shown, a cylindrical metallic casing 0, provided with flanges c and 0 for a urpose which will appear. This standard B is cut away or slotted at the bottom between said holding-screws, to make room for the heavy permanent magnet H.

The casing C supports and protects the-carbon button D, mounted therein and constituting .the delicate transmitting portion of the instrument. Button D comprises an annular wall or ring 3, closed at one side by the front electrode-4 in the form of a flexible diaphragm or disk held in place b screw-clamp rin 2 and at its other side clbsed by mica dis 8, held about its outer edge between the flange c of casin C and the ring 3.

5 is the back e ectrode, mounted upon and A screw-threaded part of e cctrode 5 passes through a central opening in disk 8 and is engaged b a screwthreaded collar 7, which clamps t e arts to the disk. A central projection 9 on t e outer end of the electrode 5 is referred to hereinafter. As will be ap arent from this explanation, both electro es are movable. The movements of relatively small amplitude impartedto the front electrode 4 corres 0nd to the carbon.

the rapidly-varying voice-currents w ich are to be relayed, and by slight variations of pressure upon the carbon mass correspondingly vary the resistance which the latter offers to the current flowing in the local circuit through The back electrode 5 remains quiescent under normal conditions, but by practice operated to overcome' boxwood spool F, centrally bore the action of the thermostatic device described hereinafter and induced by packing of the carbon receives movements of such relatively lar e amplitude as to first materially increase t e size of the carbon-chamber to loosen the carbon mass by an outward movement and to then by a reverse movement react u on the loosened, mass to scatter and distri ute the carbon particles in their chamber in a condition of normal efliciency.

E is a solid metal ring the periphery of which in part fitting closely within the central bore of standard B serves as a protection for the receiving part'of the instrument now to be described, the same consistin in part of a ii and having two flanges (Z and d, the latter of which fits closely the interior of the ring E and is secured by screws 3 to a centrally-bored metallic back G'of the instrument, a hub-like projection d from flange (Z closely fitting the bore of said back G entering therein about half-way. The spool F is wound with fine insulated wire 10, designed to be connected with the secondaries ofa triple-wound induction-coil I, in turn connected with the main wires of the main circuit, as shown at Fig. 2. In Fig. 1 these connections are by wires (not shown) to binding-post P, and a similar binding-post (not shown) on the other half of the instrument. 5

These binding-posts are insulated from the back G by mica plates m. H is a large permanent magnet bent, as shown, to embrace the greater part of the instrument of which it is itself aworking part. It is centrally located upon the base-plate A, to which it is secured by screw 8, as shown. This magnet has for its object to permanently magnetize a fixed but adjustable pole-piece e, that projects Within the bore of the spool F to within a short distance of a variable magnetic polepiece t, which latter projects within the same spool in the opposite direction from the front electrode 4, as described in my Patent No. '7 91 ,655, mentioned above.

Between the permanent magnet H and the magnetized pole-piece e is an- ;.i 'ifon block J,

held against one end of magn'etE-Hby iron screw 8 as shown, the said block -J- having near its upper end a threaded opening, into" which screws the base of a sleeve K, the forward part of which closely fits the bore of back G opposite the pro'ection d and is prevented fromturning in lock J bv a pin (not shown.) The pole-piece e is an elongation of IIO an iron thumb-screwb, working through the" sleeve K. It is furnished with an iron checknut 'n, the head of said thumb-screw b and said check-nut n being protectedby a hollow cap T, covering the whole and sc'ewing upon the rearwardly projecting end of said sleeve K. By removing the cap T and turning the thumb-screw b the gap between thefixed polepiece e and the variable pole-piece t may be adjusted to the requisite distance, as exjection 9 from ends to permit the passage of screws 8 by lained in my said Patent No. 791,655.

crews s and s secure the several parts together, as shown.

R is a heavy radiating-block secured to the standard B by screws sis and scored at 1' to now be described: Z is a flat strip of zincbroadened somewhat at the middle (see Fig. 3) to permit the assage through it of the proack electrode Sand at the which said ends are rigidly secured to the flanged casing C. The said strip is insulated from said screws and said casing by mica plates p M) .11 It is secured at'the'middle to projection 9'by a set-screw n W is an insulated resistance or heat-concentrating coil wound about said strip Z, one end of which coil is electrically connected with the back electrode 5. of chamber D through projection '9v andmetal back 6, while the other end is (in Fig. 1) connected to the binding-post P If the resistance-coil is given a resistance of twenty ohms and the zinc strip is onefourth of an inch wide and one thirtysecond' of an-inch thick, the heat developed in the coil and communicated to the strip by a normal current flowing through the carbon button when made of the ordinary dimensions and with the carbon granules in their normal unpacked condition of efliciency will be balanced. by dissipation due to conduction and radiation; butwhen the carbon granules become detrimentally packed, thereby decreasing the resistance WhichIthey offer in the local circuit, the-increased current thus permitted to circulate through coil W im arts through said coil to the zinc strip Zsu cient heat to expand the latter. As the strip is rigidly'secured at its ends, this expansion manifests itself at the middle, which is still farther bowed out, drawing out the back wall and electrode of the button D, and hence expanding the carhon-chamber and releasing pressure upon and loosenin the mass f carbon granules. It is not ,be ieved that his retreat of the ,back wall of the chamber results at once in ,the utter collapse of the packed carbon mass; although it is possible that some incipient disintegration occurs and the mass is loosened. Whatever else happens, this retreating movement of the rear wall causes the re-' sistance through the button to sudden] and strongly increase. The. current throng coil Was suddenty falls. The abnorm al heat produced by the coil W quickly disappears, and the resulting sudden contraction of strip Z forces the back wall and electrode 5'forward again, the vigor of this movement being assisted by the tendency of the resilient mica disk 8 to return. to its initial position, from which it hadbeen deflected bythe expansion of the strip Z. The carbon-containing chamber is thus contracted (for the instant to perhaps less than its normal size) and the impact exercised carbon mass distributes its component particles loosely throughout the chamber.

The manner in which the instrument is connected for use is shown at Fig. 2, although the binding-posts are there omitted. B at Fig. 2 is the local battery, a continuation Of the-winding W of the thermostat connecting with one pole thereof, while the other pole is connected. by wire 1-5 with one end of the primary 20 of induction-coil I, the other end of said primary being connected by wire '25 with the front electrode 4 of the transmittingchamber or button D. The incoming line of the circuit which it is desired to reinforce is marked 30 30, and the corresponding outgoing line is marked 40 40, or, as will be made more clear, 40 40 may be regarded as the incoming line and 30 30 as the outgoing line.

upon the already relaxed coil I, which windings have at th eir middle points the terminals 35 35 of a bridge composed of wires 50 50. This bridge is connected, as shown, with the two'ends of wire 10, designed to set up end-to-end vibrations of the variable pole 1), corresponding to voice vibrations coming. over the line. It is obvious that the currents coming over the main line in passing through the second aries 45. 45 will have an inductive effect upon the rimary 20 of the induction-coil I; but it .is ound in ractice that this effect may be ignored. he powerful vibrations, however, in the current set up in the primary 20 by the action ofthe relay and its reinforcing battery are essential, and that the effect of these vibrations maybe exerted to the best advantage the windings are all in the same direction as respects one another and relatively to the primary, as shown--that is the currents in the secondaries are all in the same ance-coil W wound around the two metals,

causes the end secured to the button D to move ,outward, thus increasing the separation between'the electrodes of the chamber or, more (particularly, between the back electrode an the granular carbon in the chamber with which the arm Z and resistance coilW aredesigned to operate.

In Fig. 5 I have illustrated the present invention as applied to an ordinary granularcarbon transmitter. give a minute description-thereof. It-is sufficient to say that the carbon-chamben and its walls as a whole are marked D The granular carbon is marked 21, the front electrode 22, the back electrode 23, while 2a and 26 are mica plates. partakes of the movements of mica plate 24, which in turn is rigidly connected with the diaphragm G: of the transmitter," asshfown, and follows its vibrations. trode 23 partakes of the movementsof mica plate 26, or, rather, by means of the-present invention causes the movement of said mica plate. Z is a zinc strip made and operatingike the zinc strip Z,heretofore. described, 28

thermal resistance and current regulatortherefor in circuit therewith, substantially as set forth.

-2. The combination, in atelephone-current reinforcer or relay apparatus, of the variable-resistance telephone-transmitting de-. vice thereof, with a thermalresistance and curiient-regulatorfor said transmitting device and in circuit therewith.

3. In a telephone-current reinforcing apparatus, the combination of the current-var in transmittin medium or s stem comb I prising the electrodes and carbon granules, of

a thermal-regulating device incircuit therewith, responsive to an abnormal fall in the resistance of said transmitting system, and adapted to rearrange said granules, and restore the normal relations of said electrodes and granules; substantially as set forth.

4. In a telephone or-telephone current relay employing granular carbon in a localc'ircuit as the transmitting ortion of the instrument, one wall of the c iambercontaining said granulated carbon being made movable, the combination with saidmovable wall and the battery or source of electromotive force in said local circuit of a thermostat adapted to It is unnecessary to The front electrode 22 The back elecbe energized by heat developed therein by of current insaid circuit due to packing of said granular carbon; and; to impart move ment to said movable electrode.

6. In a telephone-currentreinforcer or relay employing-granular carbon as the transmitting portion of the instrument, a movable back electrode forming one wall ofthe chamber containing said granular carbon, in coI'n-- bination with athermostat; the said thermostat being in a local circuit with said back electrodeand said granular carbon and being adapted to be energized by heat developed therein by increaseof current insaid local circuit and to impart movement to said move able wall.

7. In a; telephone-current reinforcer'or relay employing granular carbon as-the transmitting portion of the instrument; a movable back electrode in the chamber containing said granular carbon, in combination with a metallic strip provided with-insulated sup ports at its ends, the said strip being in mechanical connection with said back electrode and having wound aboutit an insulated resistance and heating-coil in alocal circuit including said back electrode and said granular carbon.

In testimonyv whereof I have signed my name to this specification, in the presence of two subscribing witnesses, this 23d dayof October, 1905.

HERBERT E. SHREEVE. 

